On Wed, May 30, 2012 at 03:52:34PM +0300, Felipe Balbi wrote: > On Wed, May 30, 2012 at 10:00:14AM +0200, Bjørn Mork wrote: > > We need to make sure that the USB serial driver we find > > matches the USB driver whose probe we are currently > > executing. Otherwise we will end up with USB serial > > devices bound to the correct serial driver but wrong > > USB driver. > > > > An example of such cross-probing, where the usbserial_generic > > USB driver has found the sierra serial driver: > > > > May 29 18:26:15 nemi kernel: [ 4442.559246] usbserial_generic 4-4:1.0: Sierra USB modem converter detected > > May 29 18:26:20 nemi kernel: [ 4447.556747] usbserial_generic 4-4:1.2: Sierra USB modem converter detected > > May 29 18:26:25 nemi kernel: [ 4452.557288] usbserial_generic 4-4:1.3: Sierra USB modem converter detected > > > > sysfs view of the same problem: > > > > bjorn@nemi:~$ ls -l /sys/bus/usb/drivers/sierra/ > > total 0 > > --w------- 1 root root 4096 May 29 18:23 bind > > lrwxrwxrwx 1 root root 0 May 29 18:23 module -> ../../../../module/usbserial > > --w------- 1 root root 4096 May 29 18:23 uevent > > --w------- 1 root root 4096 May 29 18:23 unbind > > bjorn@nemi:~$ ls -l /sys/bus/usb-serial/drivers/sierra/ > > total 0 > > --w------- 1 root root 4096 May 29 18:23 bind > > lrwxrwxrwx 1 root root 0 May 29 18:23 module -> ../../../../module/sierra > > -rw-r--r-- 1 root root 4096 May 29 18:23 new_id > > lrwxrwxrwx 1 root root 0 May 29 18:32 ttyUSB0 -> ../../../../devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.0/ttyUSB0 > > lrwxrwxrwx 1 root root 0 May 29 18:32 ttyUSB1 -> ../../../../devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.2/ttyUSB1 > > lrwxrwxrwx 1 root root 0 May 29 18:32 ttyUSB2 -> ../../../../devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.3/ttyUSB2 > > --w------- 1 root root 4096 May 29 18:23 uevent > > --w------- 1 root root 4096 May 29 18:23 unbind > > > > bjorn@nemi:~$ ls -l /sys/bus/usb/drivers/usbserial_generic/ > > total 0 > > lrwxrwxrwx 1 root root 0 May 29 18:33 4-4:1.0 -> ../../../../devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.0 > > lrwxrwxrwx 1 root root 0 May 29 18:33 4-4:1.2 -> ../../../../devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.2 > > lrwxrwxrwx 1 root root 0 May 29 18:33 4-4:1.3 -> ../../../../devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.3 > > --w------- 1 root root 4096 May 29 18:33 bind > > lrwxrwxrwx 1 root root 0 May 29 18:33 module -> ../../../../module/usbserial > > --w------- 1 root root 4096 May 29 18:22 uevent > > --w------- 1 root root 4096 May 29 18:33 unbind > > bjorn@nemi:~$ ls -l /sys/bus/usb-serial/drivers/generic/ > > total 0 > > --w------- 1 root root 4096 May 29 18:33 bind > > lrwxrwxrwx 1 root root 0 May 29 18:33 module -> ../../../../module/usbserial > > -rw-r--r-- 1 root root 4096 May 29 18:33 new_id > > --w------- 1 root root 4096 May 29 18:22 uevent > > --w------- 1 root root 4096 May 29 18:33 unbind > > > > So we end up with a mismatch between the USB driver and the > > USB serial driver. The reason for the above is simple: The > > USB driver probe will succeed if *any* registered serial > > driver matches, and will use that serial driver for all > > serial driver functions. > > > > This makes ref counting go wrong. We count the USB driver > > as used, but not the USB serial driver. This may result > > in Oops'es as demonstrated by Johan Hovold <jhovold@xxxxxxxxx>: > > > > [11811.646396] drivers/usb/serial/usb-serial.c: get_free_serial 1 > > [11811.646443] drivers/usb/serial/usb-serial.c: get_free_serial - minor base = 0 > > [11811.646460] drivers/usb/serial/usb-serial.c: usb_serial_probe - registering ttyUSB0 > > [11811.646766] usb 6-1: pl2303 converter now attached to ttyUSB0 > > [11812.264197] USB Serial deregistering driver FTDI USB Serial Device > > [11812.264865] usbcore: deregistering interface driver ftdi_sio > > [11812.282180] USB Serial deregistering driver pl2303 > > [11812.283141] pl2303 ttyUSB0: pl2303 converter now disconnected from ttyUSB0 > > [11812.283272] usbcore: deregistering interface driver pl2303 > > [11812.301056] USB Serial deregistering driver generic > > [11812.301186] usbcore: deregistering interface driver usbserial_generic > > [11812.301259] drivers/usb/serial/usb-serial.c: usb_serial_disconnect > > [11812.301823] BUG: unable to handle kernel paging request at f8e7438c > > [11812.301845] IP: [<f8e38445>] usb_serial_disconnect+0xb5/0x100 [usbserial] > > [11812.301871] *pde = 357ef067 *pte = 00000000 > > [11812.301957] Oops: 0000 [#1] PREEMPT SMP > > [11812.301983] Modules linked in: usbserial(-) [last unloaded: pl2303] > > [11812.302008] > > [11812.302019] Pid: 1323, comm: modprobe Tainted: G W 3.4.0-rc7+ #101 Dell Inc. Vostro 1520/0T816J > > [11812.302115] EIP: 0060:[<f8e38445>] EFLAGS: 00010246 CPU: 1 > > [11812.302130] EIP is at usb_serial_disconnect+0xb5/0x100 [usbserial] > > [11812.302141] EAX: f508a180 EBX: f508a180 ECX: 00000000 EDX: f8e74300 > > [11812.302151] ESI: f5050800 EDI: 00000001 EBP: f5141e78 ESP: f5141e58 > > [11812.302160] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 > > [11812.302170] CR0: 8005003b CR2: f8e7438c CR3: 34848000 CR4: 000007d0 > > [11812.302180] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > > [11812.302189] DR6: ffff0ff0 DR7: 00000400 > > [11812.302199] Process modprobe (pid: 1323, ti=f5140000 task=f61e2bc0 task.ti=f5140000) > > [11812.302209] Stack: > > [11812.302216] f8e3be0f f8e3b29c f8e3ae00 00000000 f513641c f5136400 f513641c f507a540 > > [11812.302325] f5141e98 c133d2c1 00000000 00000000 f509c400 f513641c f507a590 f5136450 > > [11812.302372] f5141ea8 c12f0344 f513641c f507a590 f5141ebc c12f0c67 00000000 f507a590 > > [11812.302419] Call Trace: > > [11812.302439] [<c133d2c1>] usb_unbind_interface+0x51/0x190 > > [11812.302456] [<c12f0344>] __device_release_driver+0x64/0xb0 > > [11812.302469] [<c12f0c67>] driver_detach+0x97/0xa0 > > [11812.302483] [<c12f001c>] bus_remove_driver+0x6c/0xe0 > > [11812.302500] [<c145938d>] ? __mutex_unlock_slowpath+0xcd/0x140 > > [11812.302514] [<c12f0ff9>] driver_unregister+0x49/0x80 > > [11812.302528] [<c1457df6>] ? printk+0x1d/0x1f > > [11812.302540] [<c133c50d>] usb_deregister+0x5d/0xb0 > > [11812.302557] [<f8e37c55>] ? usb_serial_deregister+0x45/0x50 [usbserial] > > [11812.302575] [<f8e37c8d>] usb_serial_deregister_drivers+0x2d/0x40 [usbserial] > > [11812.302593] [<f8e3a6e2>] usb_serial_generic_deregister+0x12/0x20 [usbserial] > > [11812.302611] [<f8e3acf0>] usb_serial_exit+0x8/0x32 [usbserial] > > [11812.302716] [<c1080b48>] sys_delete_module+0x158/0x260 > > [11812.302730] [<c110594e>] ? mntput+0x1e/0x30 > > [11812.302746] [<c145c3c3>] ? sysenter_exit+0xf/0x18 > > [11812.302746] [<c107777c>] ? trace_hardirqs_on_caller+0xec/0x170 > > [11812.302746] [<c145c390>] sysenter_do_call+0x12/0x36 > > [11812.302746] Code: 24 02 00 00 e8 dd f3 20 c8 f6 86 74 02 00 00 02 74 b4 8d 86 4c 02 00 00 47 e8 78 55 4b c8 0f b6 43 0e 39 f8 7f a9 8b 53 04 89 d8 <ff> 92 8c 00 00 00 89 d8 e8 0e ff ff ff 8b 45 f0 c7 44 24 04 2f > > [11812.302746] EIP: [<f8e38445>] usb_serial_disconnect+0xb5/0x100 [usbserial] SS:ESP 0068:f5141e58 > > [11812.302746] CR2: 00000000f8e7438c > > > > Fix by only evaluating serial drivers pointing back to the > > USB driver we are currently probing. This still allows two > > or more drivers to match the same device, running their > > serial driver probes to sort out which one to use. > > > > Cc: stable@xxxxxxxxxxxxxxx # 3.0, 3.2, 3.3, 3.4 > > Cc: Johan Hovold <jhovold@xxxxxxxxx> > > Signed-off-by: Bjørn Mork <bjorn@xxxxxxx> > > This looks fine to my eyes, FWIW: > > Reviewed-by: Felipe Balbi <balbi@xxxxxx> Seems to fix the oops as well. Before oopsing at reload you can see that somethings has gone awry as I get [ 51.054484] usbserial_generic 6-1:1.0: pl2303 converter detected when connecting the device rather than the expected [ 224.305074] pl2303 6-1:1.0: pl2303 converter detected Tested-by: Johan Hovold <jhovold@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
